on board supply control unit for a polo 2002

A wiper problem i had was traced to the control unit, my part number 6Q1937049C. I bought a new control unit part number 6Q0937049D Z01 , VW said this new part number supersedes my old one.When we fitted it the wipers work ok BUT the central locking doe not open the boot, I then got a replacement with the same part number and the boot still wouldnt open, when i put the old unit back the boot opens. Would there be different control units for 2 door and 4 door ? mines a 2 door.